Care & Handling

Esthetically, flowers and fruit combine beautifully in floral artistry, but is the combination worth losing days of flower life? Gift baskets and floral designs incorporating both fruit and flowers look terrific, but can be a death knell for some blooms. Why? Ethylene gas is the culprit. Understanding a few details about this naturally-occurring growth hormone will help you make choices about what blooms and fruits can be combined without problems.

Fruits, flowers, plants and vegetables produce ethylene and are sensitive to this odourless, colourless gas. It is called the aging hormone, and sensitivity varies among flower, fruit and plant species. It varies even between varieties within the same family – think roses: ‘Charlotte’ is quite sensitive compared to ‘Forever Young,’ which isn’t as vulnerable. Flowers that are known to be highly sensitive are treated with anti-ethylene products to ensure long life even if and/or when exposed to ethylene. Carnations and gypsophilia are good examples. Both blooms are sensitive and both are treated at farm level to protect against exposure. Treatment means the difference between flowers standing tall for 18 to 20 days versus five to six days for non-treated carnations.

When integrating flowers, plants and fruits in design, know which fruits are high ethylene producers, and which flowers and plants are highly sensitive. For example, citrus does not produce ethylene, so filling the bottom of an apothecary jar with lemons or limes and building a flower arrangement on top is fine. On the other hand, including apples in a centerpiece with green cymbidiums and asparagus fern looks terrific, but the apples will gas and kill the orchids and foliage within two to three days. Don’t include avocados in a Southwestern gift basket if agapanthus, kalanchoe or delphinium are part of the design. Ethylene is deadly in minute amounts (0.5ppm) and avocados produce lots of it! With Christmas coming, know which greens are sensitive and which are high ethylene producers so designs don’t fall apart.

Symptoms of ethylene exposure include bud and leaf abscission (falling off), poor vase life, distorted bloom opening, epinasty (stems bending down), wilting, yellowing, transparent and/or shattering petal. Besides not mixing high ethylene producing fruits with ethylene sensitive flowers, what else can you do? Know the other sources of ethylene. Cigarette and fireplace smoke, auto exhaust, non-electric forklifts, even bacteria and Botrytis (fungal disease) all produce ethylene. Take care that exhaust doesn’t flow into the shop while loading delivery vans. Enforce a “no smoking” rule in vans and make sure smoke doesn’t drift through the back door after break time. Work clean – get all bits of green trash and any infected petal parts swept up and out of the shop. Sanitize work tables and tools several times daily. Temperature is also important, as ethylene sensitivity is less problematic at temperatures colder than 40 F (4 C). Keep all fruits and vegetables (even lunches) out of flower coolers. Handle blooms with care because bruising and wounding flips on the internal ethylene switch. Ask your vendors if sensitive varieties are treated with an anti-ethylene product. Store completed gift baskets in areas with good air flow (use a fan) away from flowers.

Post this list of ethylene sensitive flowers and fruits in design area as a quick reference. When telltale symptoms of exposure appear, step up sanitation efforts. Make sure lunch remains are not tossed in trashcans in flower areas, because a half-eaten mango produces enough gas to cause the mop head hydrangea pots to flop. Airflow is very important, so use a fan or open your windows and vents. It’s important to replace the entire volume of air in a shop daily to avoid ethylene building. I mean, really, who wants to be accused of having a gas problem?

Flowers you need to protect

Here’s a list of the species that are very sensitive to ethylene and need grower-level, post-harvest treatment to protect against damage and insure a long vase life.

Agapanthus

Alstroemeria

Asclepias

Carnations/mini carns

Columbine

Cymbidiums

Delphinium species (all)

Dendrobians

Foxglove

Freesia

Gypsophilia

Holly/Ilex

Kalanchoe

Larkspur

Lilies (especially Asiatics)

Monkshood

Phlox

Physostegia

Rose varieties (some)

Saponaria

Snaps (variety dependent)

Sweet Pea

Tritoma

Wax flower

Christmas Greens to Watch

Douglas Fir and Redwood: Big ethylene producers – store away from flowers.
Juniper: Very ethylene sensitive. Also produces ethylene if infected with botrytis.
Holly and Mistletoe: Very ethylene- and temperature- sensitive
Eucalyptus: Sensitive when water stressed

Click here for a complete list of ethylene-sensitive flowers, Christmas greens, fruits, vegetables and a list of high ethylene-producing fruits and vegetables.